1. Field of the Invention
The present invention relates to a racket frame.
2. Description of the Related Art
A racket frame using FRP (fiber reinforced plastic) is known. The fiber reinforced plastic has a fiber and a matrix. The matrix is usually a resin.
Racket frames in which a rubber component is blended in the matrix are disclosed. This rubber component can enhance vibration absorbing performance.
In a racket frame described in Japanese Patent Application Publication (JP-B) No. 3401163, a matrix resin contains (meth) acrylic polymeric fine particles. The (meth)acrylic polymeric fine particles contain a rubber-like polymeric component. The (meth)acrylic polymeric particles are mixed with an epoxy resin.
JP-B No. 4213947 and JP-B No. 4252397 disclose a racket frame in which liquid rubber is blended in the matrix resin. In the racket frame of JP-B No. 4213947, the matrix resin contains rubber modified epoxy having a sea-island structure of an epoxy resin and the liquid rubber. In JP-B No. 4252397, the matrix resin contains a mixture of rubber modified epoxy and an epoxy resin containing no rubber component. The rubber modified epoxy is obtained by previously mixing and reacting the liquid rubber with the epoxy resin.
JP-B No. 3738276 discloses a racket frame having an ultra-light weight and having excellent resilience and hitting feeling. JP-B No. 3738276 regulates a frame weight, balance, (top pressure rigidity/ball-hitting face rigidity), and (ball-hitting face rigidity/throat part rigidity) or the like.
JP-B No. 4253072 discloses a racket frame tending to be treated and having excellent resilience performance. JP-B No. 4253072 regulates a product of a weight and balance, an in-plane direction rigidity value Gh in side parts of a head part, an out-of-plane direction rigidity value Gs in throat parts, a ratio (Gh/Gs), a frame weight, and balance or the like.